Coin-operated harmonograph



Jul 21, 1970 3,521,360

T. E. WULF COIN-OPERATED HARMONOGRAPH Filed April 21, 1969 5 Sheets-Sheet l 64 66 (L M v INVENTOR. THORNTON E. WULF "5- 1 ATTORNEY July 21, 1970 T.- E. WULF I 3,521,360

COIN-OPERATED HARMONOGRAPH Filed April 21, 1969 5 Sheets-Sheet 2 '24 20 j 20 32 30 3a 4o FT I] INVENTOR.

- THORNTON E. WULF Fl |5-Z ATTORNEY July 21, 1970 T. E. WULF 3,521,360

' COIN-OPERATED HARMONOGRAPH Filed April 21, 1969 x 5 Sheets-Sheet '5 v 'INVENTOR. THORNTON E. WULF Min l. QMQ

ATTORNEY July 21, 1970 I T. E. WULF 3,521,360

" COIN-OPERATED HARMONOGRAPH Filed April 21, 1969 5 Sheets-Sheet 4.

INVENTOR. THORNTON E. WULF BY V" A Q ATTORNEY July 21,1970 'T. EQWULF 3,521,360

I com-0233mm mamonoeann Filed April 21, 1969 5 Sheets-Sheet 5 INVENTOR. THORNTON E. WULF {TE-El BW J ATTORNEY United States Patent Oflice 3,521,360 Patented July 21, 1970 3,521,360 COIN-OPERATED HARMONOGRAPH Thornton E. Wull, 2902 Grandee St., Bois Idaho 83704 Filed Apr. 21, 1969, Ser. No. 817,906 Int. Cl. B431 11/00 US. C]. 33-27 12 Claims ABSTRACT OF THE DISCLOSURE A coin-operated harmonograph comprising a pendulum having a platform for the support of a removable recording sheet. A pivotally mounted recording arm is provided for holding a writing instrument for engagement with the recording sheet. Coin-operated means for normally disabling the operation of the harmonograph are provided and operation is permitted only for predetermined time periods. In one embodiment of the invention the recording arm is raised to disable recording operation, and in another, swinging of the pendulum is prevented to disable operation except for predetermined time periods. The harmonograph may include one or more pendulums, and if more than one pendulum is employed they may be independently suspended or one suspended from the other.

BACKGROUND OF THE INVENTION Harmonographs, and in particular pendulum type harmonographs, are well known as evidenced by the following U.S. Pats: Pearce No. 898,599, Worthington No. 1,869,951. Christie No. 3,143,807, Everett No. 3,324,556, and Lias No. 3,384,966, and by an article contained in Scientific American, May 1965, pages 128-136. However, none of the prior art harmonographs are controlled by coin-operated mechanism and none lend themselves to commercial exploitation. Furthermore, many prior art harmonographs are of extremely inexpensive and flimsy design and unable to withstand public use. Applicant, on the other hand, provides a rugged coin-operated harmonograph capable of withstanding rough usage by the public.

SUMMARY OF THE INVENTION An object of this invention is the provision of a coinoperated harmonograph of rugged construction, easily employed, and capable of withstanding hard usage by the general public.

The coin-operated harmonograph of this invention comprises a supporting means from which a pendulum is suspended. A platform is carried by the pendulum for the support of a recording sheet, and a vertically pivotal recording arm is located adjacent the platform for the support of a writing instrument adapted for engagement with the recording sheet. Coin-operated means for disabling operation of the harmonograph and enabling operation for predetermined periods of time upon insertion of a coin or coins therein are provided. In one arrangement the disabling means comprise a solenoid operated member engageable with the recording arm for normally supporting the arm in a raised position with the writing instrument removed from the recording sheet. Upon insertion of a coin or coins in the coin-operated means the solenoid is retracted thereby permitting the arm to lower, by gravity, for engagement of the writing instrument with the recording sheet at which time a pattern or harmonogram may be traced upon the sheet. Releaseable detent means also are provided for releaseably holding the recording arm in the raised position to permit the removal and replacement of recording sheets, and to permit the operator to obtain the desired swing of the pendulum before commencing recording of the pattern. The writing arm preferably is formed of two sections interconnected by means for disabling the writing operation if the arm is urged toward writing position without insertion of a coin or coins therein.

' In another arrangement the disabling means comprises a solenoid operated member movable into and out of the path of swinging motion of the pendulum. When extended into the path of the pendulum no regular pattern is obtainable since movement of the pendulum is restricted.

The harmonograph may comprise first and second pendulums with the second pendulum depending from the first pendulum, and the recording arm suported by the stationary pendulum supporting means. Alternatively, the first and second pendulum may be independently suspended from the supporting means, and the recording arm pivotally supported by one pendulum with the writing instrument engageable with the recording sheet carried by the platform supportedby the other pendulum. In this case the coin-operated means may be carried by the same pendulum to which the pivotally mounted recording arm is secured.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings-wherein like reference characters refer to the same parts in the several views;

FIG. 1 is a side elevational view with parts broken away showing a novel harmonograph embodying this invention,

FIG. 2 is a front elevational view of the harmonograph shown in FIG. 1,

FIG. 3 is a cross-sectional view taken along line 3-3 of FIG. 1,

FIG. 4 is an enlarged side elevational view of the recording arm and associated mechanism,

FIG. 5 is a sectional view taken substantially along line 5-5 of FIG. 4,

FIG. 6 is a fragmentary side elevational view of a modified form of disabling means for disabling the harmonograph of FIGS.-15,

FIG. 7 is a side elevational view of a modified form of harmonograph employing independently suspended pendulums,

FIG. 8 is a view which is similar to that of FIG. 4 but showing a modified form of recording arm, and

FIG. 9 is a sectional view taken along line 9-9 of FIG. 8. 7

Reference first is made to FIGS. 1-3 of the drawings wherein the harmonograph of this invention is shown comprising a pendulum supporting means 10 which includes a base formed of a pair of inwardly curved pipe members 14 interconnected adjacent the rear end thereof by base plate 16 and adjacent the forward end by a cross member 18. A pair of upwardly and generally forwardly inclined side members or legs 20 are attached to base members 14, and a third leg or member 22 is attached to the base plate 16. The legs 20 and 22 comprised a tripod at the upper end of which is attached a forwardly extending support arm 24 in the shape of an inverted channel member. With the illustrated base the operator may stand adjacent thereto without standing on the same whereby inadvertent movement of the apparatus and resulting disturbance of the swinging motion of the pendulums, described below,is avoided.

A first pendulum 26 is pivotally suspended from the arm 24 by pivotable connecting means 28. Any suitable pivotable connecting means such as a universal joint, gimbals, or the like may be employed. The illustrated pivotal connecting means 28 comprises interconnected cross arms 30 and 32 one of which arms 30 is pivotally mounted in spaced bearing blocks not shown carried by the oppositely spaced and downwardly depending side wall portions of the support arm 24. The other cross arm 32 3 pivotally supports an inverted U-shaped member 38. The pendulum 26 is attached to the base of the member 38 and is free for pivotal movement in any direction from the vertical axis.

The pendulum 26 is shown comprising a central rod 40 affixed to the inverted U-shaped member 38 and a tube or light shield 42 attached to the central rod 40 by spaced disc members 43. Any suitable means such as welding or the like not shown may be used for attaching the rod 40 to the discs 43 and the discs 43 to the light shield 42. A yoke 44 is secured to the tube 40 and rods 46 are attached to and extend downwardly from the opposite ends of the yoke for the support of a platform 50 adjacent the lower end of the rods.

The platform 50 comprises an upper plate 52 which preferably is formed of iron or other such magnetic material, which plate closes the open end of an annular container 54 and which may be secured thereto as by welding or the like. The container 54 may contain ballast or weight 56 such as sand to add to the weight of the pendulum.

Pivotal connecting means 58 which may be of the same type as connecting means 28 for suspending the upper pendulum are provided at the bottom of the platform 50 Within the center opening of the annular container 54 for the pivotal support of a second pendulum 60. The pendulum 60 is shown comprising a downwardly extending rod 62 having an axially adjustable weight 64 adjacent the lower end thereof, which weight may comprise a metallic block having a resilient bumper 66 surrounding the same. The second pendulum 60 also is free for pivotal movement in any direction from its pivotal support 58.

Preferably, but not necessarily, the lower pendulum weight 64 is substantially less than that of the weight 56 of the upper pendulum. For example only, the upper pendulum may weigh approximately 50 pounds and the lower pendulum approximately pounds. The function of the lower pendulum 60 is to perturb the motion of the upper pendulum during swinging motion thereof. It will here be understood that the device may be constructed without the lower pendulum 60 in which case the upper pendulum would swing with circular, elliptical, or straight line motion only. With the addition of the second pendulum a substantially infinite number of motion patterns for the upper pendulum is possible.

The platform 50 is adapted for the support of a record receiver or recording sheet 68 such as a sheet of paper of the like attached thereto as by tape, or the like, for easy removal and replacement thereof. In the illustrated arrangement permanent magnets 70 are shown on the paper 68 for removably attaching the paper to the platform, the magnets being magnetically attracted to the platform through the paper.

A record recorder or writing instrument such as a pen 72 is carried adjacent the outer end of the vertically pivotally mounted recording arm 74 for recording the pattern of motion of the upper pendulum 26 on the re cording sheet 68. Any suitable means may be used for removably securing the pen to the arm. In the illustrated arrangement as best seen in FIG. 5 the pen extends through the vertical aperture in the arm and is fixed in position by a lock screw 76 which extends through one portion of the bifurcated end of the arm and threadedly engages the other portion thereof for tightly clamping the pen in the arm when the lock screw is tightened.

The recording arm 74 extends from a housing or enclosure 80 fixed to the upwardly extending frame members 20 and 22 by suitable means such as welding, or the like, not shown. As seen in FIGS. 4 and 5 the inner end of the recording arm is provided with a mounting block 82 attached to the arm by means not shown and a pivot pin extends transversely of the block. The pivot pin extends between and is pivotally supported between spaced upright members 85 which in turn are attached to a bracket or base 86 which extends between and is attached to opposite side Walls of the housing 80. Suitable bearings not shown may be employed between the pin and supports to minimize pivotal frictional engagement therebetween.

A counterweight 88 is attached to the inner end of the Writing arm 74 to counterbalance the long outwardly extending arm portion of the writing arm and Writing instrument to minimize frictional engagement between the writing instrument and the paper. The writing arm preferably is made of wood or like material which serves to damp vibration of the arm and prevent chatter of the Writing instrument during recording of a pattern.

Normally the writing arm is maintained in a raised inoperative :or disabled position by means of a solenoid 89 to prevent operation of the harmonograph except for predetermined time periods dependent upon operation of a coin actuated assembly 90. Coin-operated mechanisms for controlling the supply of current to electrically operated means are well known and require no detailed description. For example the mechanism 90 may comprise an arrangement such as shown in the patent to Da'hlstrom No. 1,934,914, entitled, Prepayment Current Dispensing Device, dated Nov. 14, 1933. In the illustrated arrangement the coin actuated assembly 90- is shown comprising a coin-operated rejector mechanism 92 and time accumulator mechanism 94 both of which mechanisms are of conventional design and may be of the type manufactured by Cointrol Corporation, Forestvill, Conn. Briefly, the coin rejector mechanism 92 may include a coin receiving slot 96 as seen in FIG. 1 and into which coins may be inserted. The coins are tested as by magnets to reject ferrous coins and slugs, by sizing gates to reject undesired coins, and by a weighing station to reject coins of improper weight. Upon passing the various tests the coin momentarily closes switch contacts 98 which are diagrammatically illustrated in FIG. 4 to complete an energization circuit for the time accumulator 94. In FIG. 4 a power cord 100 for connection of the time accumulator to a conventional power source is shown together with wires 102 for conecti-ng the momentarily closed switch contacts 98 to the time accumulator.

The time accumulator 96 may simply comprise a cam actuated switch 104. The cam, designated 105, is actuated in one direction by a solenoid operated ratchet, not shown, which solenoid is momentarily energized each time the coin rejector mechanism contacts 98 are closed to rotate the ratchet and attached cam 105 a predetermined rotary distance. A timer motor connected to the cam then is energized to return the cam to a position wherein the cam actuated switch is returned to its open position, the amount of time required for the switch contacts 104 to open depending upon the number of coins inserted in the coin rejector mechanism 92.

The cam operated switch 104 is included in the actuating circuit of the solenoid 89 within the housing 80'. The solenoid 89 includes a movable, armature 108 which normally is resiliently biased as by a spring 110 into an extended position wherein the rubber cushioned end 112 engages the recording arm 74 to raise the same into an inoperative writing position as illustrated by the intermediate broken line position of the arm designated 74A shown in FIG. 4. Upon energization of the solenoid 89 by closure of the switch 104 the armature is retracted into the illustrated full line position shown in FIG. 4 thereby permitting the writing arm 74 to be lowered by gravity into operative writing position shown in full line. in FIG. 4. A dashpot 114 attached to the solenoid armature damps both the upward and downward motion of the solenoid armature.

In operation a recording sheet 68 is placed upon the platform 50 and maintained thereon by the magnets 70. The first and second pendulums 26 and 60 are swung by hand, the motion of the upper pendulum 26 being perturbed by the swinging of the lower pendulum 60. In general the most interesting patterns of motion of the platform 50 are obtained when the frequency of motion of the upper pendulum bears a whole number ratio to that of the lower pendulum, which ratio is readily varied by varying the amount or position of the weight 64 along the lower pendulum rod 62.

When the desired platform motion is obtained one or more coins are inserted in the coin slot 96 of the coin rejector mechanism 92 for actuation of the solenoid 89 to lower the recording instrument or pen 72- into engagement with'the recording sheet or a paper 68 whereupon the motion of the platform is recorded by the pen on the recording sheet. The length of time during which the design may be recorded depends upon the number of coins fed into the machine.

If during recording operation of the harmonograph it is desired to change the recording sheet 68 and/ or change the swinging motion of the pendulum, the recording arm 74 may be raised manually and maintained in the raised position by a magnetic detent means adjacent the inner end of the recording arm. In the illustrated arrangement the counterweight 88 is formed of a magnetic material such as iron and a magnet 11 6 is mounted on a bracket 1'17 therebelow. 'In the uppermost raised position of the recording arm designated 74B in FIG. 4 and shown in broken line the recording arm is shown with the counterweight 88 in engagement with the magnet 116 to maintain the recording arm in the illustrated raised position. When it is again desired to record, the arm simply is pushed downwardly to separate the counterweight from the magnet, and if the solenoid 89 is energized the recording pen is returned to engagement with the recording sheet 68.

To prevent damage to the recording arm 74 when pivoting the same either purposely or inadvertently, the arm preferably is formed of two parts or sections designated 74-1 and 74-2 interconnected by a relatively stiff coil spring 118. The adjacent ends of the arm sections are spaced apart to permit generally relative pivotal movement of the sections in any radial direction.

When the switch contacts 104 open upon expiration of the accumulated time, the solenoid 89 is deenergized whereupon the solenoid armature returns to its normally extended position to raise the arm 74 to the broken line position designated 74A and described above. The recording sheet 68 is easily moved to a different position on the platform for the formation of a plurality of nono-verlapping patterns thereon if desired.

The relative strength of the connecting spring 118 and solenoid return spring 110 is such that the spring 118 deflects before the return spring 110 compresses upon application of a downward force on the outer arm section 74-1 when the arm is in the raised position designated 74A. When the spring is so deflected, the connection between the arm sections 74-1 and 74-2 becomes so flexible that effective recording of patterns upon the sheet 68 becomes impossible. Consequently, the requirement for energizing the solenoid 89 for operation of the harmonograph may not be circumvented by simply adding weight to the recording arm. Thus, the spring connection 118 not only prevents damage to the recording arm but prevents operation of the device without insertion of the required coin or coins.

The invention having been described in detail in accordance with the requirements of the patent statutes, various changes and modifications may suggest themselves to those skilled in this art. For example, instead of disabling the writing arm 74 one of the pendulums may be normally disabled. Reference is made to FIG. 6 of the drawings wherein there is shown a fragmentary side elevational view of a modified form of coin-operated harmonograph which includes a solenoid 120 attached by brackets 122 to the frame members 20 which solenoid may be used in place of the solenoid 89. The solenoid 120 has an armature 124 movable between a retracted energized position shown in full line, and an extended deenergized position shown in broken line. The solenoid armature is connected to a power source through the time accumulator switch contacts 104, FIG. 4. When the contacts are closed the solenoid is energized to retract the armature thereby permitting unrestricted swinging of the pendulum. When the contacts are open the solenoid 120 is deenergized permitting the armature to move to the extended position in the path of the pendulum. In this position the motion of the pendulum is restricted thereby preventing normal use of the harmonograph.

Other modifications include the use of limit switches adjacent the writing arm and connected in a warning circuit for actuation of a warning bell, light, or the like, if the writing arm is deflected or pivoted beyond its normal limits. In addition, the time accumulator may be provided with another set of contacts adapted to close several seconds before the expiration of time, which contacts may be included in a warning circuit thereby indicating to the operator that additional coins are required if uninterrupted operation is desired. Further a counter may be included to record the number of coins deposited in the device.

The invention is not limited to the particular harmonograph illustrated but may be employed with different type harmonographs, a modified form of harmonograph being shown in FIG. 7 to which reference now is made. The illustrated arrangement comprises a pair of spaced upright supporting members with suitable base portions 132 at their' lower ends and a horizontal cross member 134 interconnecting the upper ends. The cross member 134 supports first and second pendulums 136 and 138 a spaced distance apart. The first pendulum 136 comprises a rod 140 attached to the cross member 134 by pivotal connecting means 28A which may be of the same type as the pivot means 28 shown in FIGS. 1 and 2 and described above. An inverted U-shaped member or bail 144 is attached to the lower end of the rod 140 for the support of a weighted platform 50B which may be of the same type as the platform 50 shown in FIGS. 1-5 and described above.

The second pendulum 138 comprises a rod 148 pivotally connected to the cross member 134 by pivotal connecting means 28B of the same type as the means 28A. A weight 64A is located adjacent the lower end of the pendulum rod 148 which weight may be adjustably positioned along the rod to change the natural frequency of oscillation of the pendulum.

A Writing arm 150 which may be of the same type as the arm 74 shown in FIGS. 1-5 is pivotally attached to the rod 148 intermediate the upper and lower ends thereof by pivot pin 151. Also attached to the rod .148 is a housing or enclosure 152 of the same type as the housing 80 of FIGS. 1-5, for the support of a coin operated rejector mechanism 92, time accumulator mechanism 94, solenoid 89, dashpot 114, and detent magnet 116 all of the same type and employed for the same purposes as like-referenced elements shown in FIGS. 1-5 and described above.

As with the harmonograph or FIGS. 1-5, the harmonograph of FIG. 7 is disabled by raising of the writing arm 150 by the solenoid 89 when the solenoid is deenergized. Upon insertion of a coin in the coin slot of the rejector mechanism 92 the solenoid is energized to retract the solenoid armature thereby permitting the writing instrument 72 of the writing arm to engage a recording sheet on the platform.

In operation before inserting the coin or coins, the writing arm is lifted to the raised position and maintained thereat by the detent magnet 1.16, a paper or recording sheet is secured to the platform 50, a coin or coins are then inserted into the coin receiving slot of the coin rejector mechanism to retract the armature of the solenoid 89, and the two pendulums 136 and 138 are placed in motion by the operator. When the desired pendulum motions are obtained the writing arm 150 is lowered and 7 the tracing of a harmonogram on the recording sheet is effected. At the end of a predetermined time period the writing arm is lifted by the solenoid 89 to terminate the pattern generation.

A modified form of writing arm designated 200 is shown in FIGS. 8 and 9 which arm may be employed in any of the embodiments of the harmonograph described above. The modified arm is shown comprising outer and inner arm sections 200-1 and 200-2 interconnected by a ball and socket connection 202. The one arm section 200-2 is provided with a forwardly extending bracket 204 which extends over the inner end of the outer arm portion 200-1, and to which a magnet 206 is attached. The arm section 200-1 has attached thereto a second magnet or magnetic element 208 adapted for cooperation with the magnet 206. A pair of guide members 210 extend downwardly from the opposite sides of the bracket 204 which members have downwardly diverging inwardly facing edges 212 for guiding the arm section 200-1 back into operative full line position shown in FIG. 8 from the broken line position. Normally, the arm sections 200-1 and 200-2 are maintained in axial alignment by magnetic attraction of the magnet 206 with the member 208. If, however, the arm section 200-1 is forced downwardly in an attempt to operate the harmonograph without first inserting a coin or coins therein to energize the solenoid 89, the magnetic attraction between elements 206 and 208 is overcome and the arm section 200-1 is free to pivot about the ball and socket connection 202. As a result, the arm section 200-1 pivotally drops by gravity into the illustrated broken line position and, at the same time, is free to rotate about its longitudinal axis whereby the writing instrument 72 is out of writing engagement with the paper 68. The apparatus is returned to operative position simply by lifting the arm section 200-1 into the full-line position. The guide members 210 serve to guide the arm section 200-1 into axial alignment with the section 200-2 when the arm section 200-1 is raised.

It is intended that the above and other such changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

I claim:

1. A harmonograph comprising,

supporting means,

a pendulum pivotally suspended from the supporting means,

a platform carried by said pendulum for the support of a recording sheet,

a pivotally mounted recording arm,

means on said recording arm for holding a writing instrument for engagement with the recording sheet, means for disabling operation of the harmonograph,

and

coin-operated means for controlling said disabling means to enable operation of the harmonograph for predetermined time periods.

2. The harmonograph as defined in claim 1 wherein said disabling means comprises means for normally sup porting the recording arm in a raised position with the writing instrument removed from the recording sheet.

3. The harmonograph as defined in claim 2 wherein said recording arm comprises axially aligned first and second spaced arm sections, and means pivotally interconnecting said first and second arm sections for normally maintaining the same in axial alignment and permitting relative pivotal movement between the arm sections upon application of excess manual force on one arm section when the arm is in the raised position.

4. The harmonograph as defined in claim 1 includ- '1 a second pendulum pivotally supported from said sup porting means,

said recording arm being pivotally secured to said sec ond pendulum,

said disabling means and said coin operated means being secured to said second pendulum for control of the pivotal recording arm between recording and inoperative conditions.

5. The harmonograph as defined in claim 1 wherein said disabling means is attached to said supporting means and is movable into the path of the pendulum to restrict swinging motion thereof.

6. The harmonograph as defined in claim 1 wherein said supporting means comprises upright members on a base of spaced members to permit operation of the harmonograph by an operator standing adjacent said base.

7. A harmonograph comprising,

supporting means,

a pendulum pivotally suspended from the supporting means,

a platform carried by said pendulum for the support of a recording sheet, a pivotally mounted recording arm, means on said recording arm for holding a writing instrument for engagement with the recording sheet,

means for normally supporting the recording arm in a raised position with the writing instrument re moved from the recording sheet for disabling operation of the harmonograph, said disabling means comprising a solenoid having a control winding and an energization circuit for the control winding, and coin operated means with contacts in the energization circuit of the solenoid control winding for control of the energization thereof for controlling said disabling means.

8. A harmonograph comprising,

supporting means,

a pendulum pivotally suspended from the supporting means,

a platform carried by said pendulum for the support of a recording sheet,

a pivotally mounted recording arm,

means on said recording arm for holding a writing instrument for engagement with the recording sheet, and

, means for normally supporting the recording arm in a raised position with the writing instrument re moved from the recording sheet for disabling operation of the harmonograph, said disabling means including a solenoid having an armature which in the deenergized condition of the solenoid supports the recording arm in said raised position.

9. A harmonograph comprising,

supporting means,

a pendulum pivotally suspended from the supporting means,

a platform carried by said pendulum for the support of a recording sheet,

a pivotally mounted recording arm,

means on said recording arm for holding a writing instrument for engagement with the recording sheet,

means movable into the path of the pendulum to restrict swinging motion thereof for disabling operation of the harmonograph, and

means including a coin-operated mechanism for controlling said disabling means to enable operation of the harmonograph.

10. A harmonograph comprising,

supporting means,

a pendulum pivotally suspended from the supporting means,

a platform carried by said pendulum for the support of a recording sheet,

a pivotally mounted recording arm comprising axially aligned first and second spaced arm sections, a coil spring surrounding adjacent ends of said first and second arm sections for normally maintaining the same in axial alignment and permitting relative pivotal movement between the arm sections upon application of excess manual force on one arm section,

means on said recording arm for holding a writing instrument for engagement with the recording sheet,

means for disabling operation of the harmonograph,

and

means for controlling said disabling means to enable operation of the harmonograph.

11. A harmonograph comprising,

supporting means,

a pendulum pivotally suspended from the supporting means,

a platform carried by said pendulum for the support of a recording sheet,

a pivotally mounted recording arm comprising axially aligned first and second spaced arm sections, ball-and-socket connecting means at the spaced ends of said arm sections, and coperative magnetic means on said first and second arm sections normally maintaining said first and second arm sections in axial alignment and permitting relative pivotal movement between the arm sections upon application of excess manual force on one arm section,

means on said recording arm for holding a writing instrument for engagement with the recording sheet,

means for disabling operation of the harmonograph,

and

means for controlling said disabling means to enable operation of the harmonograph.

12. The combination of a harmonograph Which includes a record receiver and record recorder which are relatively movable for recording of a p'atten by the recorder on the receiver upon operation of the harmonograph,

means for normally disabling operation of the harmonograph, and

coin-operated means for control of siad disabling means to enable operation of the harmonograph for predetermined time periods.

References Cited UNITED STATES PATENTS 898,599 9/1908 Pearce. 2,292,119 8/ 1942 Hackenberg et a1. 2,393,960 2/ 1946 Allen. 2,670,540 3/ 1954 Randles 3331 2,986,598 5/ 196 1 Hell. 3,015,536 1/1962 Nielsen et al. 346-136 3,384,966 5/ 1968 Lias.

FOREIGN PATENTS 887,651 8/1943 France.

HARRY N. HAROIAN, Primary Examiner 

